【作者】 陈云平；

【导师】 程贤甦；

【作者基本信息】 福州大学 ， 材料学， 2009， 博士

【摘要】 木质素是世界上第三大量的天然有机物。目前可作为工业原料的木质素主要是造纸制浆废液的副产品,其中只有少量做为初级工业品得到应用,其余绝大部分作为燃料烧掉。为了有效利用生物质资源,采用高沸醇溶剂法分离纤维素和木质素,得到了高沸醇木质素(HBSL)。选择资源丰富的花生壳、竹子和松木为植物原料,以反应温度、固液质量比、醇浓度和反应时间为因素,以HBSL提取率为目标,进行正交实验研究,得到最佳提取工艺,为HBSL产业化提供基础参数。HBSL与传统造纸工业得到的木质素产品相比,较好地保留了天然木质素所拥有的活性官能团。用传统化学方法测定HBSL的总羟值、灰份、残糖量、元素组成等数据,由此计算得到HBSL的C9结构模型。通过分析红外、紫外、核磁共振谱,研究HBSL的结构特征,并与酶解木质素比较,考察结构和官能团的异同点。通过固体超强酸催化氧化降解实验,得到了较为理想的工艺参数。采用气相色谱—质谱联用分析,可以确认降解产物中存在多种芳香族化合物,说明木质素存在多酚、多苯环结构。为将来大规模利用木质素,代替石化工业制备化工原料提供参考数据。另一方面,随着人们对可再生、可持续发展的高分子材料的密切关注,木质素改性高聚物研究不断深入。但是,受传统木质素产品化学活性差的限制,制备木质素改性材料都要预先对木质素磺酸盐或碱木素进行提纯、改性,生产工艺较为繁琐。但如果使用HBSL,可以取消纯化处理过程,直接加入HBSL或其衍生物来制备各种产品,将促进木质素的利用。HBSL改性的橡胶、环氧树脂、聚氨酯不仅可以节省石油化工原料,还达到了比较理想的改性效果。橡胶是最重要的高分子材料之一,把HBSL应用于橡胶工业,对木质素资源的充分利用有重要意义。为了提高HBSL与不同种类橡胶之间的相容性,分别对氯丁胶、丁腈胶和乙丙三元胶添加不同的HBSL衍生物。在氯丁橡胶改性中,选择环氧化HBSL作为硫化剂。对环氧化HBSL用量的影响因素进行探讨,发现在一定范围内随环氧化HBSL用量增大,对硫化胶的耐老化性能、耐溶剂性能、力学性能等都有所改善。羟甲基化后的HBSL通过共沉的方法作为补强剂用于丁腈橡胶,可以提高拉伸强度等性能。将不同原料的HBSL应用于丁腈胶,发现松木HBSL对橡胶性能提高较为有利。把HBSL与纳米SiO2制成的复合材料用于乙丙橡胶,可以有效提高断裂伸长率和耐老化性能。环氧树脂可以作为涂料、胶粘剂和工程材料,在电气、电子、光学机械、工程技术、土木建筑及文体用品制造等领域得到广泛应用。用HBSL全部或部分代替双酚A制备木质素基环氧树脂,可以减少双酚A对环境的污染,也有效地代替了石油化工原料。由于以HBSL为原料不需化学改性可以直接合成环氧树脂,节省了工艺成本,而且HBSL改性环氧树脂可以明显提高树脂涂膜的耐溶剂性、耐热性和耐老化性能。聚氨酯是近年来发展迅速的高分子弹性体。HBSL由于其丰富的醇羟基和酚羟基,替代多元醇与异氰酸酯反应可以制备木质素基聚氨酯,不仅降低成本,还可以改善聚氨酯的性能。通过探讨HBSL加入量和HBSL种类对聚氨酯性能的影响。发现HBSL可以提高聚氨酯的硬度、拉伸强度和耐溶剂性能。HBSL添加量控制在15%左右时,改性聚氨酯可以保持优良的综合性能。松木HBSL基聚氨酯对提高耐溶剂性和拉伸强度更为有利,而花生壳HBSL对提高聚氨酯断裂伸长率更好。更多还原

【Abstract】 Lignin is the third abundant organic substance in nature. Presently, most industrial lignin products were produced from the black liquid of pulp and paper industry. Only small amount of them were used to prepare lignin sulfonate, and others were burned as fuel. For efficacious application of biomass resources, the high boiling solvent method was developed to produce high boiling solvent lignin (HBSL). In order to obtain the optimum technology for HBSL extraction, orthogonal experiments were carried out on peanut shell, bamboo, and masson pine. The effects of some factors on the extraction of HBSL were studied, such as reaction temperature, mass ratio of solid to liquid, concentration of solvent and reaction time. This research will lay a foundation for industrial application of lignin resources.Compared with traditional lignin products, more functional groups were well preserved in HBSL. The general hydroxyl value, ash content, residual polysaccharide content, and element composition of HBSL were investigated by traditional chemical methods. The C9formula of HBSL was then calculated by these basic data of chemical groups. The structure characteristics of HBSL were analyzed by FT-IR, UV and NMR spectrum. The similarities and the differences in structure and functional groups between enzymatic hydrolysis lignin and HBSL were also discussed.The optimum conditions were acquired by degrading HBSL with solid super acid as a catalyst. The aromatic substance was confirmed by GC-MS analysis in the degradation products of HBSL, which indicated that HBSL contained polyhydroxybenzene or polybenzene compound. The research on the degradation of lignin provided a reference for the potential application of HBSL in replacing petrochemical materials in the future.Moreover, as a natural polymer, lignin was renewable and biodegradable. With the increasingly serious problems of environmental pollution and the crisis of oil resources, more and more attention has been paid to the use of renewable and degradable natural polymer. Due to the defects of traditional lignin, the purification and modification are usually necessary before using lignosulfate or alkali lignin effectively. However, HBSL can be used in various fields without the process of purification or modification because of its high chemical activity and purity. HBSL has successfully been used in modifing rubber, epoxy resin and polyurethane. Results show that it can not only reduce the consumption of petrochemical materials, but also improve some properties of the polymers.Rubber is one of most important polymer materials and the application of HBSL in rubber industry is of great significance. The compatibility of HBSL derivatives with different rubbers were investigated, including chloroprene rubber (CR), nitrile butadiene rubber (NBR) and ethylene propylene diene methylene (EPDM). The epoxidized HBSL could be used as a curing agent in CR and the amount of it was an important factor affecting the properties of CR. The anti-aging, solvent resistance and the mechanical properties of CR were improved with increasing amount of epoxidized HBSL. The tensile strength of NBR was improved when the hydromethyl modified HBSL was added by coprecipitating HBSL with NBR. The breaking elongation and the anti-aging property of EPDM were also improved when the composite material of HBSL/nano-silica was added.Epoxy resin has been used as dope, adhesive or engineering material in many fields. In the process of making the lignin based epoxy resin, biphenol-A (BPA) was replaced by HBSL entirely or partly, which may not only minimize the potential pollution of BPA but also reduce the cost effectively. HBSL could be used directly in epoxy resin preparation without further modification. The solvent resistance and the thermal endurance properties of the modified epoxy resin were improved considerably.Polyurethane was a macromolecule elastomer developed rapidly in recent years. Since HBSL had abundant aliphatic and phenolic hydroxyl groups which could substitute polyol to react with the isocyanate, HBSL was used in polyurethane synthesis in this article. The rigidity, tensile strength and solvent resistance of polyurethane were improved by adding appropriate amount of HBSL. The best performance of polyurethane could be achieved when the lignin dosage was about15%. The masson pine HBSL modified polyurethane had favorable solvent resistance and tensile strength; while the peanut shell HBSL modified polyurethane performed well in breaking elongation test.更多还原